/**\mainpage
 * Copyright (C) 2016 - 2017 Bosch Sensortec GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * Neither the name of the copyright holder nor the names of the
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
 * OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
 *
 * The information provided is believed to be accurate and reliable.
 * The copyright holder assumes no responsibility
 * for the consequences of use
 * of such information nor for any infringement of patents or
 * other rights of third parties which may result from its use.
 * No license is granted by implication or otherwise under any patent or
 * patent rights of the copyright holder.
 *
 * File		bme280.c
 * Date		14 Feb 2018
 * Version	3.3.4
 *
 */

/*! @file bme280.c
    @brief Sensor driver for BME280 sensor */
#include "bme280.h"

/**\name Internal macros */
/* To identify osr settings selected by user */
#define OVERSAMPLING_SETTINGS UINT8_C(0x07)
/* To identify filter and standby settings selected by user */
#define FILTER_STANDBY_SETTINGS UINT8_C(0x18)

/*!
 * @brief This internal API puts the device to sleep mode.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 *
 * @return Result of API execution status.
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t put_device_to_sleep(const struct bme280_dev *dev);

/*!
 * @brief This internal API writes the power mode in the sensor.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[in] sensor_mode : Variable which contains the power mode to be set.
 *
 * @return Result of API execution status.
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t write_power_mode(uint8_t sensor_mode, const struct bme280_dev *dev);

/*!
 * @brief This internal API is used to validate the device pointer for
 * null conditions.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t null_ptr_check(const struct bme280_dev *dev);

/*!
 * @brief This internal API interleaves the register address between the
 * register data buffer for burst write operation.
 *
 * @param[in] reg_addr : Contains the register address array.
 * @param[out] temp_buff : Contains the temporary buffer to store the
 * register data and register address.
 * @param[in] reg_data : Contains the register data to be written in the
 * temporary buffer.
 * @param[in] len : No of bytes of data to be written for burst write.
 */
static void interleave_reg_addr(const uint8_t *reg_addr, uint8_t *temp_buff, const uint8_t *reg_data, uint8_t len);

/*!
 * @brief This internal API reads the calibration data from the sensor, parse
 * it and store in the device structure.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t get_calib_data(struct bme280_dev *dev);

/*!
 *  @brief This internal API is used to parse the temperature and
 *  pressure calibration data and store it in the device structure.
 *
 *  @param[out] dev : Structure instance of bme280_dev to store the calib data.
 *  @param[in] reg_data : Contains the calibration data to be parsed.
 */
static void parse_temp_press_calib_data(const uint8_t *reg_data, struct bme280_dev *dev);

/*!
 *  @brief This internal API is used to parse the humidity calibration data
 *  and store it in device structure.
 *
 *  @param[out] dev : Structure instance of bme280_dev to store the calib data.
 *  @param[in] reg_data : Contains calibration data to be parsed.
 */
static void parse_humidity_calib_data(const uint8_t *reg_data, struct bme280_dev *dev);

#ifdef BME280_FLOAT_ENABLE
/*!
 * @brief This internal API is used to compensate the raw pressure data and
 * return the compensated pressure data in double data type.
 *
 * @param[in] uncomp_data : Contains the uncompensated pressure data.
 * @param[in] calib_data : Pointer to the calibration data structure.
 *
 * @return Compensated pressure data.
 * @retval Compensated pressure data in double.
 */
static double compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                  const struct bme280_calib_data *calib_data);

/*!
 * @brief This internal API is used to compensate the raw humidity data and
 * return the compensated humidity data in double data type.
 *
 * @param[in] uncomp_data : Contains the uncompensated humidity data.
 * @param[in] calib_data : Pointer to the calibration data structure.
 *
 * @return Compensated humidity data.
 * @retval Compensated humidity data in double.
 */
static double compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                  const struct bme280_calib_data *calib_data);

/*!
 * @brief This internal API is used to compensate the raw temperature data and
 * return the compensated temperature data in double data type.
 *
 * @param[in] uncomp_data : Contains the uncompensated temperature data.
 * @param[in] calib_data : Pointer to calibration data structure.
 *
 * @return Compensated temperature data.
 * @retval Compensated temperature data in double.
 */
static double compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                     struct bme280_calib_data *calib_data);

#else

/*!
 * @brief This internal API is used to compensate the raw temperature data and
 * return the compensated temperature data in integer data type.
 *
 * @param[in] uncomp_data : Contains the uncompensated temperature data.
 * @param[in] calib_data : Pointer to calibration data structure.
 *
 * @return Compensated temperature data.
 * @retval Compensated temperature data in integer.
 */
static int32_t compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                      struct bme280_calib_data *calib_data);

/*!
 * @brief This internal API is used to compensate the raw pressure data and
 * return the compensated pressure data in integer data type.
 *
 * @param[in] uncomp_data : Contains the uncompensated pressure data.
 * @param[in] calib_data : Pointer to the calibration data structure.
 *
 * @return Compensated pressure data.
 * @retval Compensated pressure data in integer.
 */
static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data);

/*!
 * @brief This internal API is used to compensate the raw humidity data and
 * return the compensated humidity data in integer data type.
 *
 * @param[in] uncomp_data : Contains the uncompensated humidity data.
 * @param[in] calib_data : Pointer to the calibration data structure.
 *
 * @return Compensated humidity data.
 * @retval Compensated humidity data in integer.
 */
static uint32_t compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data);

#endif

/*!
 * @brief This internal API is used to identify the settings which the user
 * wants to modify in the sensor.
 *
 * @param[in] sub_settings : Contains the settings subset to identify particular
 * group of settings which the user is interested to change.
 * @param[in] desired_settings : Contains the user specified settings.
 *
 * @return Indicates whether user is interested to modify the settings which
 * are related to sub_settings.
 * @retval True -> User wants to modify this group of settings
 * @retval False -> User does not want to modify this group of settings
 */
static uint8_t are_settings_changed(uint8_t sub_settings, uint8_t desired_settings);

/*!
 * @brief This API sets the humidity oversampling settings of the sensor.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t set_osr_humidity_settings(const struct bme280_settings *settings, const struct bme280_dev *dev);

/*!
 * @brief This internal API sets the oversampling settings for pressure,
 * temperature and humidity in the sensor.
 *
 * @param[in] desired_settings : Variable used to select the settings which
 * are to be set.
 * @param[in] dev : Structure instance of bme280_dev.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t set_osr_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                               const struct bme280_dev *dev);

/*!
 * @brief This API sets the pressure and/or temperature oversampling settings
 * in the sensor according to the settings selected by the user.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[in] desired_settings: variable to select the pressure and/or
 * temperature oversampling settings.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t set_osr_press_temp_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                                          const struct bme280_dev *dev);

/*!
 * @brief This internal API fills the pressure oversampling settings provided by
 * the user in the data buffer so as to write in the sensor.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[out] reg_data : Variable which is filled according to the pressure
 * oversampling data provided by the user.
 */
static void fill_osr_press_settings(uint8_t *reg_data, const struct bme280_settings *settings);

/*!
 * @brief This internal API fills the temperature oversampling settings provided
 * by the user in the data buffer so as to write in the sensor.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[out] reg_data : Variable which is filled according to the temperature
 * oversampling data provided by the user.
 */
static void fill_osr_temp_settings(uint8_t *reg_data, const struct bme280_settings *settings);

/*!
 * @brief This internal API sets the filter and/or standby duration settings
 * in the sensor according to the settings selected by the user.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[in] desired_settings : variable to select the filter and/or
 * standby duration settings.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t set_filter_standby_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                                          const struct bme280_dev *dev);

/*!
 * @brief This internal API fills the filter settings provided by the user
 * in the data buffer so as to write in the sensor.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[out] reg_data : Variable which is filled according to the filter
 * settings data provided by the user.
 */
static void fill_filter_settings(uint8_t *reg_data, const struct bme280_settings *settings);

/*!
 * @brief This internal API fills the standby duration settings provided by the
 * user in the data buffer so as to write in the sensor.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[out] reg_data : Variable which is filled according to the standby
 * settings data provided by the user.
 */
static void fill_standby_settings(uint8_t *reg_data, const struct bme280_settings *settings);

/*!
 * @brief This internal API parse the oversampling(pressure, temperature
 * and humidity), filter and standby duration settings and store in the
 * device structure.
 *
 * @param[out] dev : Structure instance of bme280_dev.
 * @param[in] reg_data : Register data to be parsed.
 */
static void parse_device_settings(const uint8_t *reg_data, struct bme280_settings *settings);

/*!
 * @brief This internal API reloads the already existing device settings in the
 * sensor after soft reset.
 *
 * @param[in] dev : Structure instance of bme280_dev.
 * @param[in] settings : Pointer variable which contains the settings to
 * be set in the sensor.
 *
 * @return Result of API execution status
 * @retval zero -> Success / +ve value -> Warning / -ve value -> Error
 */
static int8_t reload_device_settings(const struct bme280_settings *settings, const struct bme280_dev *dev);

/****************** Global Function Definitions *******************************/

/*!
 *  @brief This API is the entry point.
 *  It reads the chip-id and calibration data from the sensor.
 */
int8_t bme280_init(struct bme280_dev *dev)
{
  int8_t rslt;
  /* chip id read try count */
  uint8_t try_count = 10;
  uint8_t chip_id = 0;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);
  /* Proceed if null check is fine */
  if (rslt == BME280_OK)
  {
    while (try_count)
    {
      /* Read the chip-id of bme280 sensor */
      rslt = bme280_get_regs(BME280_CHIP_ID_ADDR, &chip_id, 1, dev);
      /* Check for chip id validity */
      if ((rslt == BME280_OK) && (chip_id == BME280_CHIP_ID))
      {
        dev->chip_id = chip_id;
        /* Reset the sensor */
        rslt = bme280_soft_reset(dev);
        if (rslt == BME280_OK)
        {
          /* Read the calibration data */
          rslt = get_calib_data(dev);
        }
        break;
      }
      /* Wait for 1 ms */
      dev->delay_ms(1);
      --try_count;
    }
    /* Chip id check failed */
    if (!try_count)
      rslt = BME280_E_DEV_NOT_FOUND;
  }
  return rslt;
}

/*!
 * @brief This API reads the data from the given register address of the sensor.
 */
int8_t bme280_get_regs(uint8_t reg_addr, uint8_t *reg_data, uint16_t len, const struct bme280_dev *dev)
{
  int8_t rslt;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);
  /* Proceed if null check is fine */
  if (rslt == BME280_OK)
  {
    /* If interface selected is SPI */
    if (dev->intf != BME280_I2C_INTF)
      reg_addr = reg_addr | 0x80;
    /* Read the data  */
    rslt = dev->read(dev->dev_id, reg_addr, reg_data, len);
    /* Check for communication error */
    if (rslt != BME280_OK)
      rslt = BME280_E_COMM_FAIL;
  }

  return rslt;
}

/*!
 * @brief This API writes the given data to the register address
 * of the sensor.
 */
int8_t bme280_set_regs(uint8_t *reg_addr, const uint8_t *reg_data, uint8_t len, const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t temp_buff[20]; /* Typically not to write more than 10 registers */

  if (len > 10)
    len = 10;

  uint16_t temp_len;
  uint8_t reg_addr_cnt;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);
  /* Check for arguments validity */
  if ((rslt == BME280_OK) && (reg_addr != NULL) && (reg_data != NULL))
  {
    if (len != 0)
    {
      temp_buff[0] = reg_data[0];
      /* If interface selected is SPI */
      if (dev->intf != BME280_I2C_INTF)
      {
        for (reg_addr_cnt = 0; reg_addr_cnt < len; reg_addr_cnt++)
          reg_addr[reg_addr_cnt] = reg_addr[reg_addr_cnt] & 0x7F;
      }
      /* Burst write mode */
      if (len > 1)
      {
        /* Interleave register address w.r.t data for
        burst write*/
        interleave_reg_addr(reg_addr, temp_buff, reg_data, len);
        temp_len = ((len * 2) - 1);
      }
      else
      {
        temp_len = len;
      }
      rslt = dev->write(dev->dev_id, reg_addr[0], temp_buff, temp_len);
      /* Check for communication error */
      if (rslt != BME280_OK)
        rslt = BME280_E_COMM_FAIL;
    }
    else
    {
      rslt = BME280_E_INVALID_LEN;
    }
  }
  else
  {
    rslt = BME280_E_NULL_PTR;
  }

  return rslt;
}

/*!
 * @brief This API sets the oversampling, filter and standby duration
 * (normal mode) settings in the sensor.
 */
int8_t bme280_set_sensor_settings(uint8_t desired_settings, const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t sensor_mode;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);
  /* Proceed if null check is fine */
  if (rslt == BME280_OK)
  {
    rslt = bme280_get_sensor_mode(&sensor_mode, dev);
    if ((rslt == BME280_OK) && (sensor_mode != BME280_SLEEP_MODE))
      rslt = put_device_to_sleep(dev);
    if (rslt == BME280_OK)
    {
      /* Check if user wants to change oversampling
         settings */
      if (are_settings_changed(OVERSAMPLING_SETTINGS, desired_settings))
        rslt = set_osr_settings(desired_settings, &dev->settings, dev);
      /* Check if user wants to change filter and/or
         standby settings */
      if ((rslt == BME280_OK) && are_settings_changed(FILTER_STANDBY_SETTINGS, desired_settings))
        rslt = set_filter_standby_settings(desired_settings, &dev->settings, dev);
    }
  }

  return rslt;
}

/*!
 * @brief This API gets the oversampling, filter and standby duration
 * (normal mode) settings from the sensor.
 */
int8_t bme280_get_sensor_settings(struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_data[4];

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);
  /* Proceed if null check is fine */
  if (rslt == BME280_OK)
  {
    rslt = bme280_get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4, dev);
    if (rslt == BME280_OK)
      parse_device_settings(reg_data, &dev->settings);
  }

  return rslt;
}

/*!
 * @brief This API sets the power mode of the sensor.
 */
int8_t bme280_set_sensor_mode(uint8_t sensor_mode, const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t last_set_mode;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);

  if (rslt == BME280_OK)
  {
    rslt = bme280_get_sensor_mode(&last_set_mode, dev);
    /* If the sensor is not in sleep mode put the device to sleep
       mode */
    if ((rslt == BME280_OK) && (last_set_mode != BME280_SLEEP_MODE))
      rslt = put_device_to_sleep(dev);
    /* Set the power mode */
    if (rslt == BME280_OK)
      rslt = write_power_mode(sensor_mode, dev);
  }

  return rslt;
}

/*!
 * @brief This API gets the power mode of the sensor.
 */
int8_t bme280_get_sensor_mode(uint8_t *sensor_mode, const struct bme280_dev *dev)
{
  int8_t rslt;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);

  if (rslt == BME280_OK)
  {
    /* Read the power mode register */
    rslt = bme280_get_regs(BME280_PWR_CTRL_ADDR, sensor_mode, 1, dev);
    /* Assign the power mode in the device structure */
    *sensor_mode = BME280_GET_BITS_POS_0(*sensor_mode, BME280_SENSOR_MODE);
  }

  return rslt;
}

/*!
 * @brief This API performs the soft reset of the sensor.
 */
int8_t bme280_soft_reset(const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_addr = BME280_RESET_ADDR;
  /* 0xB6 is the soft reset command */
  uint8_t soft_rst_cmd = 0xB6;

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);
  /* Proceed if null check is fine */
  if (rslt == BME280_OK)
  {
    /* Write the soft reset command in the sensor */
    rslt = bme280_set_regs(&reg_addr, &soft_rst_cmd, 1, dev);
    /* As per data sheet, startup time is 2 ms. */
    dev->delay_ms(2);
  }

  return rslt;
}

/*!
 * @brief This API reads the pressure, temperature and humidity data from the
 * sensor, compensates the data and store it in the bme280_data structure
 * instance passed by the user.
 */
int8_t bme280_get_sensor_data(uint8_t sensor_comp, struct bme280_data *comp_data, struct bme280_dev *dev)
{
  int8_t rslt;
  /* Array to store the pressure, temperature and humidity data read from
  the sensor */
  uint8_t reg_data[BME280_P_T_H_DATA_LEN] = {0};
  struct bme280_uncomp_data uncomp_data = {0};

  /* Check for null pointer in the device structure*/
  rslt = null_ptr_check(dev);

  if ((rslt == BME280_OK) && (comp_data != NULL))
  {
    /* Read the pressure and temperature data from the sensor */
    rslt = bme280_get_regs(BME280_DATA_ADDR, reg_data, BME280_P_T_H_DATA_LEN, dev);

    if (rslt == BME280_OK)
    {
      /* Parse the read data from the sensor */
      bme280_parse_sensor_data(reg_data, &uncomp_data);
      /* Compensate the pressure and/or temperature and/or
         humidity data from the sensor */
      rslt = bme280_compensate_data(sensor_comp, &uncomp_data, comp_data, &dev->calib_data);
    }
  }
  else
  {
    rslt = BME280_E_NULL_PTR;
  }

  return rslt;
}

/*!
 *  @brief This API is used to parse the pressure, temperature and
 *  humidity data and store it in the bme280_uncomp_data structure instance.
 */
void bme280_parse_sensor_data(const uint8_t *reg_data, struct bme280_uncomp_data *uncomp_data)
{
  /* Variables to store the sensor data */
  uint32_t data_xlsb;
  uint32_t data_lsb;
  uint32_t data_msb;

  /* Store the parsed register values for pressure data */
  data_msb = (uint32_t)reg_data[0] << 12;
  data_lsb = (uint32_t)reg_data[1] << 4;
  data_xlsb = (uint32_t)reg_data[2] >> 4;
  uncomp_data->pressure = data_msb | data_lsb | data_xlsb;

  /* Store the parsed register values for temperature data */
  data_msb = (uint32_t)reg_data[3] << 12;
  data_lsb = (uint32_t)reg_data[4] << 4;
  data_xlsb = (uint32_t)reg_data[5] >> 4;
  uncomp_data->temperature = data_msb | data_lsb | data_xlsb;

  /* Store the parsed register values for temperature data */
  data_lsb = (uint32_t)reg_data[6] << 8;
  data_msb = (uint32_t)reg_data[7];
  uncomp_data->humidity = data_msb | data_lsb;
}

/*!
 * @brief This API is used to compensate the pressure and/or
 * temperature and/or humidity data according to the component selected
 * by the user.
 */
int8_t bme280_compensate_data(uint8_t sensor_comp, const struct bme280_uncomp_data *uncomp_data,
                              struct bme280_data *comp_data, struct bme280_calib_data *calib_data)
{
  int8_t rslt = BME280_OK;

  if ((uncomp_data != NULL) && (comp_data != NULL) && (calib_data != NULL))
  {
    /* Initialize to zero */
    comp_data->temperature = 0;
    comp_data->pressure = 0;
    comp_data->humidity = 0;
    /* If pressure or temperature component is selected */
    if (sensor_comp & (BME280_PRESS | BME280_TEMP | BME280_HUM))
    {
      /* Compensate the temperature data */
      comp_data->temperature = compensate_temperature(uncomp_data, calib_data);
    }
    if (sensor_comp & BME280_PRESS)
    {
      /* Compensate the pressure data */
      comp_data->pressure = compensate_pressure(uncomp_data, calib_data);
    }
    if (sensor_comp & BME280_HUM)
    {
      /* Compensate the humidity data */
      comp_data->humidity = compensate_humidity(uncomp_data, calib_data);
    }
  }
  else
  {
    rslt = BME280_E_NULL_PTR;
  }

  return rslt;
}

/*!
 * @brief This internal API sets the oversampling settings for pressure,
 * temperature and humidity in the sensor.
 */
static int8_t set_osr_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                               const struct bme280_dev *dev)
{
  int8_t rslt = BME280_W_INVALID_OSR_MACRO;

  if (desired_settings & BME280_OSR_HUM_SEL)
    rslt = set_osr_humidity_settings(settings, dev);
  if (desired_settings & (BME280_OSR_PRESS_SEL | BME280_OSR_TEMP_SEL))
    rslt = set_osr_press_temp_settings(desired_settings, settings, dev);

  return rslt;
}

/*!
 * @brief This API sets the humidity oversampling settings of the sensor.
 */
static int8_t set_osr_humidity_settings(const struct bme280_settings *settings, const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t ctrl_hum;
  uint8_t ctrl_meas;
  uint8_t reg_addr = BME280_CTRL_HUM_ADDR;

  ctrl_hum = settings->osr_h & BME280_CTRL_HUM_MSK;
  /* Write the humidity control value in the register */
  rslt = bme280_set_regs(&reg_addr, &ctrl_hum, 1, dev);
  /* Humidity related changes will be only effective after a
     write operation to ctrl_meas register */
  if (rslt == BME280_OK)
  {
    reg_addr = BME280_CTRL_MEAS_ADDR;
    rslt = bme280_get_regs(reg_addr, &ctrl_meas, 1, dev);
    if (rslt == BME280_OK)
      rslt = bme280_set_regs(&reg_addr, &ctrl_meas, 1, dev);
  }

  return rslt;
}

/*!
 * @brief This API sets the pressure and/or temperature oversampling settings
 * in the sensor according to the settings selected by the user.
 */
static int8_t set_osr_press_temp_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                                          const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_addr = BME280_CTRL_MEAS_ADDR;
  uint8_t reg_data;

  rslt = bme280_get_regs(reg_addr, &reg_data, 1, dev);

  if (rslt == BME280_OK)
  {
    if (desired_settings & BME280_OSR_PRESS_SEL)
      fill_osr_press_settings(&reg_data, settings);
    if (desired_settings & BME280_OSR_TEMP_SEL)
      fill_osr_temp_settings(&reg_data, settings);
    /* Write the oversampling settings in the register */
    rslt = bme280_set_regs(&reg_addr, &reg_data, 1, dev);
  }

  return rslt;
}

/*!
 * @brief This internal API sets the filter and/or standby duration settings
 * in the sensor according to the settings selected by the user.
 */
static int8_t set_filter_standby_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                                          const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_addr = BME280_CONFIG_ADDR;
  uint8_t reg_data;

  rslt = bme280_get_regs(reg_addr, &reg_data, 1, dev);

  if (rslt == BME280_OK)
  {
    if (desired_settings & BME280_FILTER_SEL)
      fill_filter_settings(&reg_data, settings);
    if (desired_settings & BME280_STANDBY_SEL)
      fill_standby_settings(&reg_data, settings);
    /* Write the oversampling settings in the register */
    rslt = bme280_set_regs(&reg_addr, &reg_data, 1, dev);
  }

  return rslt;
}

/*!
 * @brief This internal API fills the filter settings provided by the user
 * in the data buffer so as to write in the sensor.
 */
static void fill_filter_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
  *reg_data = BME280_SET_BITS(*reg_data, BME280_FILTER, settings->filter);
}

/*!
 * @brief This internal API fills the standby duration settings provided by
 * the user in the data buffer so as to write in the sensor.
 */
static void fill_standby_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
  *reg_data = BME280_SET_BITS(*reg_data, BME280_STANDBY, settings->standby_time);
}

/*!
 * @brief This internal API fills the pressure oversampling settings provided by
 * the user in the data buffer so as to write in the sensor.
 */
static void fill_osr_press_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
  *reg_data = BME280_SET_BITS(*reg_data, BME280_CTRL_PRESS, settings->osr_p);
}

/*!
 * @brief This internal API fills the temperature oversampling settings
 * provided by the user in the data buffer so as to write in the sensor.
 */
static void fill_osr_temp_settings(uint8_t *reg_data, const struct bme280_settings *settings)
{
  *reg_data = BME280_SET_BITS(*reg_data, BME280_CTRL_TEMP, settings->osr_t);
}

/*!
 * @brief This internal API parse the oversampling(pressure, temperature
 * and humidity), filter and standby duration settings and store in the
 * device structure.
 */
static void parse_device_settings(const uint8_t *reg_data, struct bme280_settings *settings)
{
  settings->osr_h = BME280_GET_BITS_POS_0(reg_data[0], BME280_CTRL_HUM);
  settings->osr_p = BME280_GET_BITS(reg_data[2], BME280_CTRL_PRESS);
  settings->osr_t = BME280_GET_BITS(reg_data[2], BME280_CTRL_TEMP);
  settings->filter = BME280_GET_BITS(reg_data[3], BME280_FILTER);
  settings->standby_time = BME280_GET_BITS(reg_data[3], BME280_STANDBY);
}
/*!
 * @brief This internal API writes the power mode in the sensor.
 */
static int8_t write_power_mode(uint8_t sensor_mode, const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_addr = BME280_PWR_CTRL_ADDR;
  /* Variable to store the value read from power mode register */
  uint8_t sensor_mode_reg_val;

  /* Read the power mode register */
  rslt = bme280_get_regs(reg_addr, &sensor_mode_reg_val, 1, dev);
  /* Set the power mode */
  if (rslt == BME280_OK)
  {
    sensor_mode_reg_val = BME280_SET_BITS_POS_0(sensor_mode_reg_val, BME280_SENSOR_MODE, sensor_mode);
    /* Write the power mode in the register */
    rslt = bme280_set_regs(&reg_addr, &sensor_mode_reg_val, 1, dev);
  }

  return rslt;
}

/*!
 * @brief This internal API puts the device to sleep mode.
 */
static int8_t put_device_to_sleep(const struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_data[4];
  struct bme280_settings settings;

  rslt = bme280_get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4, dev);
  if (rslt == BME280_OK)
  {
    parse_device_settings(reg_data, &settings);
    rslt = bme280_soft_reset(dev);
    if (rslt == BME280_OK)
      rslt = reload_device_settings(&settings, dev);
  }

  return rslt;
}

/*!
 * @brief This internal API reloads the already existing device settings in
 * the sensor after soft reset.
 */
static int8_t reload_device_settings(const struct bme280_settings *settings, const struct bme280_dev *dev)
{
  int8_t rslt;

  rslt = set_osr_settings(BME280_ALL_SETTINGS_SEL, settings, dev);
  if (rslt == BME280_OK)
    rslt = set_filter_standby_settings(BME280_ALL_SETTINGS_SEL, settings, dev);

  return rslt;
}

#ifdef BME280_FLOAT_ENABLE
/*!
 * @brief This internal API is used to compensate the raw temperature data and
 * return the compensated temperature data in double data type.
 */
static double compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                     struct bme280_calib_data *calib_data)
{
  double var1;
  double var2;
  double temperature;
  double temperature_min = -40;
  double temperature_max = 85;

  var1 = ((double)uncomp_data->temperature) / 16384.0 - ((double)calib_data->dig_T1) / 1024.0;
  var1 = var1 * ((double)calib_data->dig_T2);
  var2 = (((double)uncomp_data->temperature) / 131072.0 - ((double)calib_data->dig_T1) / 8192.0);
  var2 = (var2 * var2) * ((double)calib_data->dig_T3);
  calib_data->t_fine = (int32_t)(var1 + var2);
  temperature = (var1 + var2) / 5120.0;

  if (temperature < temperature_min)
    temperature = temperature_min;
  else if (temperature > temperature_max)
    temperature = temperature_max;

  return temperature;
}

/*!
 * @brief This internal API is used to compensate the raw pressure data and
 * return the compensated pressure data in double data type.
 */
static double compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                  const struct bme280_calib_data *calib_data)
{
  double var1;
  double var2;
  double var3;
  double pressure;
  double pressure_min = 30000.0;
  double pressure_max = 110000.0;

  var1 = ((double)calib_data->t_fine / 2.0) - 64000.0;
  var2 = var1 * var1 * ((double)calib_data->dig_P6) / 32768.0;
  var2 = var2 + var1 * ((double)calib_data->dig_P5) * 2.0;
  var2 = (var2 / 4.0) + (((double)calib_data->dig_P4) * 65536.0);
  var3 = ((double)calib_data->dig_P3) * var1 * var1 / 524288.0;
  var1 = (var3 + ((double)calib_data->dig_P2) * var1) / 524288.0;
  var1 = (1.0 + var1 / 32768.0) * ((double)calib_data->dig_P1);
  /* avoid exception caused by division by zero */
  if (var1)
  {
    pressure = 1048576.0 - (double)uncomp_data->pressure;
    pressure = (pressure - (var2 / 4096.0)) * 6250.0 / var1;
    var1 = ((double)calib_data->dig_P9) * pressure * pressure / 2147483648.0;
    var2 = pressure * ((double)calib_data->dig_P8) / 32768.0;
    pressure = pressure + (var1 + var2 + ((double)calib_data->dig_P7)) / 16.0;

    if (pressure < pressure_min)
      pressure = pressure_min;
    else if (pressure > pressure_max)
      pressure = pressure_max;
  }
  else
  { /* Invalid case */
    pressure = pressure_min;
  }

  return pressure;
}

/*!
 * @brief This internal API is used to compensate the raw humidity data and
 * return the compensated humidity data in double data type.
 */
static double compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                  const struct bme280_calib_data *calib_data)
{
  double humidity;
  double humidity_min = 0.0;
  double humidity_max = 100.0;
  double var1;
  double var2;
  double var3;
  double var4;
  double var5;
  double var6;

  var1 = ((double)calib_data->t_fine) - 76800.0;
  var2 = (((double)calib_data->dig_H4) * 64.0 + (((double)calib_data->dig_H5) / 16384.0) * var1);
  var3 = uncomp_data->humidity - var2;
  var4 = ((double)calib_data->dig_H2) / 65536.0;
  var5 = (1.0 + (((double)calib_data->dig_H3) / 67108864.0) * var1);
  var6 = 1.0 + (((double)calib_data->dig_H6) / 67108864.0) * var1 * var5;
  var6 = var3 * var4 * (var5 * var6);
  humidity = var6 * (1.0 - ((double)calib_data->dig_H1) * var6 / 524288.0);

  if (humidity > humidity_max)
    humidity = humidity_max;
  else if (humidity < humidity_min)
    humidity = humidity_min;

  return humidity;
}

#else
/*!
 * @brief This internal API is used to compensate the raw temperature data and
 * return the compensated temperature data in integer data type.
 */
static int32_t compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                      struct bme280_calib_data *calib_data)
{
  int32_t var1;
  int32_t var2;
  int32_t temperature;
  int32_t temperature_min = -4000;
  int32_t temperature_max = 8500;

  var1 = (int32_t)((uncomp_data->temperature / 8) - ((int32_t)calib_data->dig_T1 * 2));
  var1 = (var1 * ((int32_t)calib_data->dig_T2)) / 2048;
  var2 = (int32_t)((uncomp_data->temperature / 16) - ((int32_t)calib_data->dig_T1));
  var2 = (((var2 * var2) / 4096) * ((int32_t)calib_data->dig_T3)) / 16384;
  calib_data->t_fine = var1 + var2;
  temperature = (calib_data->t_fine * 5 + 128) / 256;

  if (temperature < temperature_min)
    temperature = temperature_min;
  else if (temperature > temperature_max)
    temperature = temperature_max;

  return temperature;
}
#ifdef BME280_64BIT_ENABLE
/*!
 * @brief This internal API is used to compensate the raw pressure data and
 * return the compensated pressure data in integer data type with higher
 * accuracy.
 */
static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data)
{
  int64_t var1;
  int64_t var2;
  int64_t var3;
  int64_t var4;
  uint32_t pressure;
  uint32_t pressure_min = 3000000;
  uint32_t pressure_max = 11000000;

  var1 = ((int64_t)calib_data->t_fine) - 128000;
  var2 = var1 * var1 * (int64_t)calib_data->dig_P6;
  var2 = var2 + ((var1 * (int64_t)calib_data->dig_P5) * 131072);
  var2 = var2 + (((int64_t)calib_data->dig_P4) * 34359738368);
  var1 = ((var1 * var1 * (int64_t)calib_data->dig_P3) / 256) + ((var1 * ((int64_t)calib_data->dig_P2) * 4096));
  var3 = ((int64_t)1) * 140737488355328;
  var1 = (var3 + var1) * ((int64_t)calib_data->dig_P1) / 8589934592;

  /* To avoid divide by zero exception */
  if (var1 != 0)
  {
    var4 = 1048576 - uncomp_data->pressure;
    var4 = (((var4 * 2147483648) - var2) * 3125) / var1;
    var1 = (((int64_t)calib_data->dig_P9) * (var4 / 8192) * (var4 / 8192)) / 33554432;
    var2 = (((int64_t)calib_data->dig_P8) * var4) / 524288;
    var4 = ((var4 + var1 + var2) / 256) + (((int64_t)calib_data->dig_P7) * 16);
    pressure = (uint32_t)(((var4 / 2) * 100) / 128);

    if (pressure < pressure_min)
      pressure = pressure_min;
    else if (pressure > pressure_max)
      pressure = pressure_max;
  }
  else
  {
    pressure = pressure_min;
  }

  return pressure;
}
#else
/*!
 * @brief This internal API is used to compensate the raw pressure data and
 * return the compensated pressure data in integer data type.
 */
static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data)
{
  int32_t var1;
  int32_t var2;
  int32_t var3;
  int32_t var4;
  uint32_t var5;
  uint32_t pressure;
  uint32_t pressure_min = 30000;
  uint32_t pressure_max = 110000;

  var1 = (((int32_t)calib_data->t_fine) / 2) - (int32_t)64000;
  var2 = (((var1 / 4) * (var1 / 4)) / 2048) * ((int32_t)calib_data->dig_P6);
  var2 = var2 + ((var1 * ((int32_t)calib_data->dig_P5)) * 2);
  var2 = (var2 / 4) + (((int32_t)calib_data->dig_P4) * 65536);
  var3 = (calib_data->dig_P3 * (((var1 / 4) * (var1 / 4)) / 8192)) / 8;
  var4 = (((int32_t)calib_data->dig_P2) * var1) / 2;
  var1 = (var3 + var4) / 262144;
  var1 = (((32768 + var1)) * ((int32_t)calib_data->dig_P1)) / 32768;
  /* avoid exception caused by division by zero */
  if (var1)
  {
    var5 = (uint32_t)((uint32_t)1048576) - uncomp_data->pressure;
    pressure = ((uint32_t)(var5 - (uint32_t)(var2 / 4096))) * 3125;
    if (pressure < 0x80000000)
      pressure = (pressure << 1) / ((uint32_t)var1);
    else
      pressure = (pressure / (uint32_t)var1) * 2;

    var1 = (((int32_t)calib_data->dig_P9) * ((int32_t)(((pressure / 8) * (pressure / 8)) / 8192))) / 4096;
    var2 = (((int32_t)(pressure / 4)) * ((int32_t)calib_data->dig_P8)) / 8192;
    pressure = (uint32_t)((int32_t)pressure + ((var1 + var2 + calib_data->dig_P7) / 16));

    if (pressure < pressure_min)
      pressure = pressure_min;
    else if (pressure > pressure_max)
      pressure = pressure_max;
  }
  else
  {
    pressure = pressure_min;
  }

  return pressure;
}
#endif

/*!
 * @brief This internal API is used to compensate the raw humidity data and
 * return the compensated humidity data in integer data type.
 */
static uint32_t compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data)
{
  int32_t var1;
  int32_t var2;
  int32_t var3;
  int32_t var4;
  int32_t var5;
  uint32_t humidity;
  uint32_t humidity_max = 102400;

  var1 = calib_data->t_fine - ((int32_t)76800);
  var2 = (int32_t)(uncomp_data->humidity * 16384);
  var3 = (int32_t)(((int32_t)calib_data->dig_H4) * 1048576);
  var4 = ((int32_t)calib_data->dig_H5) * var1;
  var5 = (((var2 - var3) - var4) + (int32_t)16384) / 32768;
  var2 = (var1 * ((int32_t)calib_data->dig_H6)) / 1024;
  var3 = (var1 * ((int32_t)calib_data->dig_H3)) / 2048;
  var4 = ((var2 * (var3 + (int32_t)32768)) / 1024) + (int32_t)2097152;
  var2 = ((var4 * ((int32_t)calib_data->dig_H2)) + 8192) / 16384;
  var3 = var5 * var2;
  var4 = ((var3 / 32768) * (var3 / 32768)) / 128;
  var5 = var3 - ((var4 * ((int32_t)calib_data->dig_H1)) / 16);
  var5 = (var5 < 0 ? 0 : var5);
  var5 = (var5 > 419430400 ? 419430400 : var5);
  humidity = (uint32_t)(var5 / 4096);

  if (humidity > humidity_max)
    humidity = humidity_max;

  return humidity;
}
#endif

/*!
 * @brief This internal API reads the calibration data from the sensor, parse
 * it and store in the device structure.
 */
static int8_t get_calib_data(struct bme280_dev *dev)
{
  int8_t rslt;
  uint8_t reg_addr = BME280_TEMP_PRESS_CALIB_DATA_ADDR;
  /* Array to store calibration data */
  uint8_t calib_data[BME280_TEMP_PRESS_CALIB_DATA_LEN] = {0};

  /* Read the calibration data from the sensor */
  rslt = bme280_get_regs(reg_addr, calib_data, BME280_TEMP_PRESS_CALIB_DATA_LEN, dev);

  if (rslt == BME280_OK)
  {
    /* Parse temperature and pressure calibration data and store
       it in device structure */
    parse_temp_press_calib_data(calib_data, dev);

    reg_addr = BME280_HUMIDITY_CALIB_DATA_ADDR;
    /* Read the humidity calibration data from the sensor */
    rslt = bme280_get_regs(reg_addr, calib_data, BME280_HUMIDITY_CALIB_DATA_LEN, dev);
    if (rslt == BME280_OK)
    {
      /* Parse humidity calibration data and store it in
         device structure */
      parse_humidity_calib_data(calib_data, dev);
    }
  }

  return rslt;
}

/*!
 * @brief This internal API interleaves the register address between the
 * register data buffer for burst write operation.
 */
static void interleave_reg_addr(const uint8_t *reg_addr, uint8_t *temp_buff, const uint8_t *reg_data, uint8_t len)
{
  uint8_t index;

  for (index = 1; index < len; index++)
  {
    temp_buff[(index * 2) - 1] = reg_addr[index];
    temp_buff[index * 2] = reg_data[index];
  }
}

/*!
 *  @brief This internal API is used to parse the temperature and
 *  pressure calibration data and store it in device structure.
 */
static void parse_temp_press_calib_data(const uint8_t *reg_data, struct bme280_dev *dev)
{
  struct bme280_calib_data *calib_data = &dev->calib_data;

  calib_data->dig_T1 = BME280_CONCAT_BYTES(reg_data[1], reg_data[0]);
  calib_data->dig_T2 = (int16_t)BME280_CONCAT_BYTES(reg_data[3], reg_data[2]);
  calib_data->dig_T3 = (int16_t)BME280_CONCAT_BYTES(reg_data[5], reg_data[4]);
  calib_data->dig_P1 = BME280_CONCAT_BYTES(reg_data[7], reg_data[6]);
  calib_data->dig_P2 = (int16_t)BME280_CONCAT_BYTES(reg_data[9], reg_data[8]);
  calib_data->dig_P3 = (int16_t)BME280_CONCAT_BYTES(reg_data[11], reg_data[10]);
  calib_data->dig_P4 = (int16_t)BME280_CONCAT_BYTES(reg_data[13], reg_data[12]);
  calib_data->dig_P5 = (int16_t)BME280_CONCAT_BYTES(reg_data[15], reg_data[14]);
  calib_data->dig_P6 = (int16_t)BME280_CONCAT_BYTES(reg_data[17], reg_data[16]);
  calib_data->dig_P7 = (int16_t)BME280_CONCAT_BYTES(reg_data[19], reg_data[18]);
  calib_data->dig_P8 = (int16_t)BME280_CONCAT_BYTES(reg_data[21], reg_data[20]);
  calib_data->dig_P9 = (int16_t)BME280_CONCAT_BYTES(reg_data[23], reg_data[22]);
  calib_data->dig_H1 = reg_data[25];
}

/*!
 *  @brief This internal API is used to parse the humidity calibration data
 *  and store it in device structure.
 */
static void parse_humidity_calib_data(const uint8_t *reg_data, struct bme280_dev *dev)
{
  struct bme280_calib_data *calib_data = &dev->calib_data;
  int16_t dig_H4_lsb;
  int16_t dig_H4_msb;
  int16_t dig_H5_lsb;
  int16_t dig_H5_msb;

  calib_data->dig_H2 = (int16_t)BME280_CONCAT_BYTES(reg_data[1], reg_data[0]);
  calib_data->dig_H3 = reg_data[2];

  dig_H4_msb = (int16_t)(int8_t)reg_data[3] * 16;
  dig_H4_lsb = (int16_t)(reg_data[4] & 0x0F);
  calib_data->dig_H4 = dig_H4_msb | dig_H4_lsb;

  dig_H5_msb = (int16_t)(int8_t)reg_data[5] * 16;
  dig_H5_lsb = (int16_t)(reg_data[4] >> 4);
  calib_data->dig_H5 = dig_H5_msb | dig_H5_lsb;
  calib_data->dig_H6 = (int8_t)reg_data[6];
}

/*!
 * @brief This internal API is used to identify the settings which the user
 * wants to modify in the sensor.
 */
static uint8_t are_settings_changed(uint8_t sub_settings, uint8_t desired_settings)
{
  uint8_t settings_changed = FALSE;

  if (sub_settings & desired_settings)
  {
    /* User wants to modify this particular settings */
    settings_changed = TRUE;
  }
  else
  {
    /* User don't want to modify this particular settings */
    settings_changed = FALSE;
  }

  return settings_changed;
}

/*!
 * @brief This internal API is used to validate the device structure pointer for
 * null conditions.
 */
static int8_t null_ptr_check(const struct bme280_dev *dev)
{
  int8_t rslt;

  if ((dev == NULL) || (dev->read == NULL) || (dev->write == NULL) || (dev->delay_ms == NULL))
  {
    /* Device structure pointer is not valid */
    rslt = BME280_E_NULL_PTR;
  }
  else
  {
    /* Device structure is fine */
    rslt = BME280_OK;
  }

  return rslt;
}
